Fears about childhood obesity have led a United States education authority to ban the sale of fizzy drinks in school.

The Philadelphia school district, one of the biggest in the US, has approved the toughest measures so far against fizzy drinks in school.

The ban will mean that from July, vending machines in schools will only be allowed to sell fruit juice, water and milk drinks.

School officials say this will improve nutrition and reduce obesity.

Obesity

"It is fitting that our new policy is approved just weeks after the American Academy of Pediatrics urged school districts to restrict soda sales in order to reduce the risk of obesity," said the head of the city's school district, Paul Vallas.

Drinks which will be allowed

100% fruit juice with no artificial sweeteners

Drinking water with no additives

Milk and flavoured milks

Drinks not to exceed 12 ounces for younger children, 16 ounces for older

"We need to do all we can to offer nutritious choices for our students."

The city's strict policy on the sale of fizzy, sugary drinks has followed a long process of consultation and debate - but has been formally adoped by education officials and will be implemented in five months.

Philadelphia's "beverage policy" is the latest shift in attitude towards young people's diet in the United States - with growing concern about obesity and lack of fitness.

There have already been moves by school authorities in New York to reduce access to fizzy drinks - and Philadelphia's decision will add to the pressure to end the practice of selling fizzy drinks through vending machines on school premises.

Many US schools and school districts receive a regular income from the sale of fizzy drinks - with some authorities having agreements with individual drinks companies.